Radio telephone system with one-to-many dispatch system

Abstract

A one-to-many dispatch method for use in a TDMA or other wireless telephone system. The one-to-many dispatch call is placed by sending a Request message 204 from a Personal Station PS 112 to a Control Center Station (CS) 120 which assigns a channel with an Assignment message 208 . The PS 112 sends a call setup message over the control channel resulting in a channel assign message 242 being broadcast repeatedly. Call connect messages over the Assigned Channel AC 244 are also repeated from the CS 120 to indicate the open connection. A hang timer is started when the PS 112 ceases transmission of voice and the connection is torn down upon expiry of the hang timer unless another PS transmits a call setup message 234 on the Assigned Channel AC before the expiry of the hang timer.

What is claimed is:  
     
       1. A method of carrying out a one-to-many Dispatch call among members of a talkgroup on a telephone system, comprising: 
       over a Control Channel, establishing an Assigned Communication Channel for sending a call setup message from a personal station having a personal station ID to a Control Station, using a Request message containing a talkgroup ID for the talkgroup;  
       sending gather messages containing the talkgroup ID on a common Paging Channel PC;  
       sending connect messages containing the first personal station ID on the Assigned Communication Channel indicating to the first personal station the right to transmit information on the communications channel;  
       transmitting information from the first personal station on the Assigned Communication Channel;  
       detecting a signal loss in the transmitted information; and  
       initiating a dropout timer.  
     
     
       2. The method in accordance with  claim 1 , further comprising: 
       transmitting connect messages containing the first personal station ID on the Assigned Communication Channel for a duration of the dropout timer.  
     
     
       3. The method in accordance with  claim 1 , further comprising: 
       transmitting release messages over the Assigned Communication Channel after the duration of the dropout timer expires.  
     
     
       4. The method in accordance with  claim 2 , further comprising: 
       receiving an information transmission from the first personal station during said dropout timer; and  
       stopping the dropout timer in response to receiving the information transmission.